Allow the utility_meter to net meter rather than only allow increases.

homeassistant/components/utility_meter/__init__.py

@@ -12,9 +12,9 @@
 from homeassistant.components.sensor import DOMAIN as SENSOR_DOMAIN
 from .const import (
     DOMAIN, SIGNAL_RESET_METER, METER_TYPES, CONF_SOURCE_SENSOR,
-    CONF_METER_TYPE, CONF_METER_OFFSET, CONF_TARIFF_ENTITY, CONF_TARIFF,
-    CONF_TARIFFS, CONF_METER, DATA_UTILITY, SERVICE_RESET,
-    SERVICE_SELECT_TARIFF, SERVICE_SELECT_NEXT_TARIFF,
+    CONF_METER_TYPE, CONF_METER_OFFSET, CONF_METER_NET_CONSUMPTION,
+    CONF_TARIFF_ENTITY, CONF_TARIFF, CONF_TARIFFS, CONF_METER, DATA_UTILITY,
+    SERVICE_RESET, SERVICE_SELECT_TARIFF, SERVICE_SELECT_NEXT_TARIFF,
     ATTR_TARIFF)
 
 _LOGGER = logging.getLogger(__name__)
@@ -36,6 +36,7 @@
     vol.Optional(CONF_NAME): cv.string,
     vol.Optional(CONF_METER_TYPE): vol.In(METER_TYPES),
     vol.Optional(CONF_METER_OFFSET, default=0): cv.positive_int,
+    vol.Optional(CONF_METER_NET_CONSUMPTION, default=False): cv.boolean,
     vol.Optional(CONF_TARIFFS, default=[]): vol.All(
         cv.ensure_list, [cv.string]),
 })

homeassistant/components/utility_meter/const.py

@@ -15,6 +15,7 @@
 CONF_SOURCE_SENSOR = 'source'
 CONF_METER_TYPE = 'cycle'
 CONF_METER_OFFSET = 'offset'
+CONF_METER_NET_CONSUMPTION = 'net_consumption'
 CONF_PAUSED = 'paused'
 CONF_TARIFFS = 'tariffs'
 CONF_TARIFF = 'tariff'

homeassistant/components/utility_meter/sensor.py

@@ -17,7 +17,7 @@
     DATA_UTILITY, SIGNAL_RESET_METER,
     HOURLY, DAILY, WEEKLY, MONTHLY, YEARLY,
     CONF_SOURCE_SENSOR, CONF_METER_TYPE, CONF_METER_OFFSET,
-    CONF_TARIFF, CONF_TARIFF_ENTITY, CONF_METER)
+    CONF_METER_NET_CONSUMPTION, CONF_TARIFF, CONF_TARIFF_ENTITY, CONF_METER)
 
 _LOGGER = logging.getLogger(__name__)
 
@@ -48,22 +48,24 @@ async def async_setup_platform(
         conf_meter_source = hass.data[DATA_UTILITY][meter][CONF_SOURCE_SENSOR]
         conf_meter_type = hass.data[DATA_UTILITY][meter].get(CONF_METER_TYPE)
         conf_meter_offset = hass.data[DATA_UTILITY][meter][CONF_METER_OFFSET]
+        conf_meter_net_consumption =\
+            hass.data[DATA_UTILITY][meter][CONF_METER_NET_CONSUMPTION]
         conf_meter_tariff_entity = hass.data[DATA_UTILITY][meter].get(
             CONF_TARIFF_ENTITY)
 
         meters.append(UtilityMeterSensor(
             conf_meter_source, conf.get(CONF_NAME), conf_meter_type,
-            conf_meter_offset, conf.get(CONF_TARIFF),
-            conf_meter_tariff_entity))
+            conf_meter_offset, conf_meter_net_consumption,
+            conf.get(CONF_TARIFF), conf_meter_tariff_entity))
 
     async_add_entities(meters)
 
 
 class UtilityMeterSensor(RestoreEntity):
     """Representation of an utility meter sensor."""
 
-    def __init__(self, source_entity, name, meter_type, meter_offset=0,
-                 tariff=None, tariff_entity=None):
+    def __init__(self, source_entity, name, meter_type, meter_offset,
+                 net_consumption, tariff=None, tariff_entity=None):
         """Initialize the Utility Meter sensor."""
         self._sensor_source_id = source_entity
         self._state = 0
@@ -77,6 +79,7 @@ def __init__(self, source_entity, name, meter_type, meter_offset=0,
         self._unit_of_measurement = None
         self._period = meter_type
         self._period_offset = meter_offset
+        self._sensor_net_consumption = net_consumption
         self._tariff = tariff
         self._tariff_entity = tariff_entity
 
@@ -96,7 +99,7 @@ def async_reading(self, entity, old_state, new_state):
         try:
             diff = Decimal(new_state.state) - Decimal(old_state.state)
 
-            if diff < 0:
+            if (not self._sensor_net_consumption) and diff < 0:
                 # Source sensor just rolled over for unknow reasons,
                 return
             self._state += diff

tests/components/utility_meter/test_sensor.py

@@ -57,6 +57,72 @@ async def test_state(hass):
     assert state.state == '1'
 
 
+async def test_net_consumption(hass):
+    """Test utility sensor state."""
+    config = {
+        'utility_meter': {
+            'energy_bill': {
+                'source': 'sensor.energy',
+                'net_consumption': True
+            }
+        }
+    }
+
+    assert await async_setup_component(hass, DOMAIN, config)
+    assert await async_setup_component(hass, SENSOR_DOMAIN, config)
+    await hass.async_block_till_done()
+
+    hass.bus.async_fire(EVENT_HOMEASSISTANT_START)
+    entity_id = config[DOMAIN]['energy_bill']['source']
+    hass.states.async_set(entity_id, 2, {"unit_of_measurement": "kWh"})
+    await hass.async_block_till_done()
+
+    now = dt_util.utcnow() + timedelta(seconds=10)
+    with patch('homeassistant.util.dt.utcnow',
+               return_value=now):
+        hass.states.async_set(entity_id, 1, {"unit_of_measurement": "kWh"},
+                              force_update=True)
+        await hass.async_block_till_done()
+
+    state = hass.states.get('sensor.energy_bill')
+    assert state is not None
+
+    assert state.state == '-1'
+
+
+async def test_non_net_consumption(hass):
+    """Test utility sensor state."""
+    config = {
+        'utility_meter': {
+            'energy_bill': {
+                'source': 'sensor.energy',
+                'net_consumption': False
+            }
+        }
+    }
+
+    assert await async_setup_component(hass, DOMAIN, config)
+    assert await async_setup_component(hass, SENSOR_DOMAIN, config)
+    await hass.async_block_till_done()
+
+    hass.bus.async_fire(EVENT_HOMEASSISTANT_START)
+    entity_id = config[DOMAIN]['energy_bill']['source']
+    hass.states.async_set(entity_id, 2, {"unit_of_measurement": "kWh"})
+    await hass.async_block_till_done()
+
+    now = dt_util.utcnow() + timedelta(seconds=10)
+    with patch('homeassistant.util.dt.utcnow',
+               return_value=now):
+        hass.states.async_set(entity_id, 1, {"unit_of_measurement": "kWh"},
+                              force_update=True)
+        await hass.async_block_till_done()
+
+    state = hass.states.get('sensor.energy_bill')
+    assert state is not None
+
+    assert state.state == '0'
+
+
 async def _test_self_reset(hass, cycle, start_time, expect_reset=True):
     """Test energy sensor self reset."""
     config = {